“It is a pretty uncommon bacteria and usually requires that you have some kind of cut or wound on your hand or arm that serves as a way for the bacteria to enter your body,” Dr. Jay Varma, the department’s Deputy Commissioner for Disease Control, told 1010 WINS.

Symptoms include red, tender lumps and swelling under the skin of their hands or arms. Sometimes people also develop swelling or pain in their hands or arms and have difficulty moving their fingers.

“And then invading deeper into tendons and muscles of the hands so people will have pain and difficulty moving their hands and know something bad is going on,” Dr. Varma told TV 10/55’s John Slattery.

Dr. Varma added that recent cases have involved people who had pre-existing cuts on their hands and came into contact with the fish, or injured themselves while preparing it.

“Because this infection can look like any other common skin infection, a number of people have gone weeks and sometimes even months before they’ve had an accurate diagnosis,” Varma said.

The infection is treatable by antibiotics.

The Health Department is urging people to wear waterproof gloves when handling raw fish that came from a Chinatown market.

One woman was not happy to hear about a problem with fish on the first day of Lent.

“I’m just hearing about this. It gets me really worried that I could get that disease, because there’s a lot of stuff going around,” she said.

Varma said the investigation is ongoing.

“This is a very uncommon bacteria so the fact that we’ve detected 30 cases so far suggests that something has changed, either about the water in the tank or the tanks themselves or the types of fish or seafood that are causing this problem,” Varma said. “We’re still in the process of investigating all of the cases, that includes interviewing them and finding out which markets they specifically shopped at and what types of fish they actually bought.”